Elevator control system



July 7, 1936. E. M. BOUTON AL 2,046,722

ELEVATOR com- 0; SQISATEM Filed Oct. 304, 1935 "lfivznioai William A. 6'lark and m Q I 0 a mm m F W 2 n w WITNESSES:

Patented July $933 lnghouse Electric illonapat @hicago, Hit, a corporation oi Application @ctoher Elli, lddii, genial Not di it-i2 Our invention relates to control systems and more particularly to systems ior controlling the operation of electric elevators, hoists similar apparatus.

In elevator installations embodying variable voltage and other systems of control or the Ward-Leonard type, it has been found uneconomical to keep the operating means or driving motor of the motor generator set in con= tinuous operation under its own power where the elevator service required is not constant at all times but is intermittent in character.

This will be apparent when it is considered that-although the driving motor for the genera tor in variable voltage control systems must have sufficient capacity for its ordinary operating load, its continuous operation during long periods of time when the elevator is idle, results in lowering the power :iactor or the supply circuit to an undesirable degree and the no-load losses, when operating under a no-load condition, for a large proportion of its time, become large in proportion to the useful power consumed "while the elevator is operating for the purpose or carrying passengers. In some'systems of this character, the driving motor may be disconnected from its source of electrical energy and a small auxiliary motor may be used for maintaining the driving motor at its normal speed while it is so disconnected, so that the elevator motor may he placed in operation at any time simply by reconnecting the driving motor to its source of supply.

One object of our invention is to provide a simple and inexpensive means ior connecting and disconnecting the driving motor of the above-mentioned systems from its source of supply.

Another object is to provide a system of this character which shall eliminate any flickering of lamps in the elevator system caused by the connecting and disconnecting oi the driving m0- tor from its source of electrical energmwhen the car is being placed in active condition and inactive condition.

It is also an object to provide for eliminating the very high magnetizing peak in the driving motor which usually occurs during the first few cycles of its operation when it is thrown directly on the line while it is running at its normal speed.

For a better understanding of our invention reference may be had to the accompanying drawing, the sole figure of which is a diagrammatic representation of an elevator system embodying our invention.

lei. t aitite) A variable voltage system oi control may be 10 provided for operating the hoisting motor EM wherein the armature Eli/i of the hoisting motor is connected in-loop circuit with the armature G of a generator G. The generator G is provided with a series field winding GS? and a sep- 15 aratelyexcited field "winding Gi The armature G oi the generator G is suitably driven by means of a main driving motor M. The motor Tl/l comprises a squirrel cage rotor i and a three phase, star connected stator winding 20 Md. The outer leads of the stator winding are connected by a line switch 5 to a suitable source of electrical energy represented by the supply conductors Ll, L2 and L3.

A direct current exciter E having a shunt field 25 winding EF and. an armature E is disposed on the shaft oi the driving motor for providing a. direct current source of excitation for the field winding GF of the generator, the field winding nun or the elevator hoisting motor, and for opcratingv the various control switches, signal lamps, etc. for the elevator.

The direction of the excitation current for the field winding GI of the generator may be suitably controlled by means of an up direction switch l and a down direction switch 2. The value oi the current supplied to the field winding or may be controlled by a resistor R which may be controlled through a speed relay 3.

A car switch CS is disposed in the car C ior controlling the up and down direction switches i and 2 for operating the hoisting motor to start and stop the'car C and for controlling the operation of the elevator doors (not shown) through the agency of a door closing relay 45. The contact members b on the relay '45 areprovided for the door operating circuits (not shown).

In elevator installations of the nature shown, a small auxiliary motor AM comprising a rotor AM and a stator winding AMS is provided for maintaining the driving motor M in constant operation at its normal speed while the car is not being operated. The winding AIMS is directly connected to the contact membeis oi. the

G to rotate at-normal speed by reason of their.

being mounted upon the common driving shaft 20. By this system the motor generator set is started and is maintained at its normal speed by the auxiliary motor AM while the car' is not in operation so that it will be ready for opera-. tion at any instant that the attendant on the' car desires to start the car through operating the car switch CS. It will also be apparent that inasmuch as the driving motor M is not yet connected to itssource of electrical energy because of open switches in its winding MS, it is not incurring no-load losses and is not afiecting the power factor of the supply circuit in any way.

In prior systems using an auxiliary motor it has been the practice to connect the'driving motor to a source of energy when the car is to be'started, by closing a three-pole switch in the main supply line. It has been necessary to use a three-pole switch, because when a two-pole switch is placed in the line of an alternatingcurrent motor, it unbalances the motor to a certain extent, at least to such an extent as-to make it unavailable for use in elevator systems where noiseless operation is essential. Also, the prior practice of throwing the motor directly on the line resulted in the occurrence of a very high magnetizing peak in the motor during its first few cycles of operation. This high mag netizing peak causes various, disturbances, ln-.

eluding flickering of the lamps in the elevator system, by reason of the constant throwing oil and on of the motor.

In order to eliminate these diificulties and provide' a more economical construction, wehave disposed a two-pole switch it in the central connectors of the star winding in the driving motor, and have also provided a buffer resistance RI, R2 and R3, controlled by an accelerating switch H] for the center of the star winding, and have connected these switches in the control system in such manner that an' excedin gly smooth operation is secured when the system is placed in operation.

A time limit relay 1? is also provided for con trolling the operation of the motor accelerating switch I I. The time limit relay is provided with a dashpot MDT to delay its operation for a predetermined period after it is demagnetized.

An overload relay 8 is disposed in the circuit leading to the windings AMS, and an overload relay 9 is disposed in the circuit leading to both the windings MS and AMS. The contact members 8a and 9a, of the overload relays are dis-,

posed in the circuit of the line switch 5 to open that switch and thereby disconnect the motors from their supply circuit when any overload condition occurs in either motor.

It is believed that the invention maybe best understood by considering the following assumed operation of the system shown.

It will be assumed that the system is placed in operation by'the car attendant closing a switch 5S which may be disposed in the' car C or at any other suitable point. The operation of the switch 5S energizes the line switch 5 by com-- pleting a circuit extending from the supply conductor L2 through a protecting fuse t, switch 58, the coil of switch 5 and the contact meir'r bers 8a and 9a of overload relays 8 and 9 to he supply conductor L3. The energization of the line switch 5 causes it to close its contact members 5a., 5b, and 50, thereby connecting the windings AMS of the auxiliary motor AM to the supply conductors Ll, L2 and L3. The energization of the windings AMS causes the motor AM to start in operation, thereby rotating the shaft 21 and causing the motor M, the exciterE and the generator G'to operate at their normal rate of rotation.

It is understood that the small auxiliary motor AMis sofdesigned in relation to the motor M, the exciter E, and the generator G that it will cause them to operate at their normal speed while the elevator car 6 is not being operated by the hoisting motor EM. Hence, the driving motor M is always maintained in constant operation at its "normalrate of rotation and is always in condition to take up the operation of the elevator car at' any instant that the car attendant. decides to move the car.

- 'Ihe.operation' of the exciter E causes its voltage to buildupto its normal amount, usually approximately 230 volts, whereupon it energizes the time limit relay l2 to close its contact members 12a and open its contact members I2b. The closing of the contact members I2a will permit energization of the driving motor switch l0, but the opening of the contact members l2b will prevent energization of the accelerating switch I l until the expiration of a predetermined period of time after the time limit relay I2 is deenergized.

It will be assumed now that the car attendant decides to move the car upwardly, and, therefore,- operates the car switch CS in a counterclockwise direction. The first movement of the switch CS closes its "contact members i3 and H, thereby energizing 'the door closing relay 45 to efi'ect the closing of the car door (not shown) by acircuit-extending from the supply conductor L+ through conductor l5, contact members l3 and I4, conductor iii, the coil of relaytiand conductor 57 to the supply conductor L The door closing relay is normally so associated with the door operating means (not shown) that it causes the closing of the elevator door (not'shown), but, inasmuch as this is old bers @211. of the time limit relay i2, effect the i energization of the motor switch it by a circuit extending from the supply conductor L+ through the contact members a, the coil of relay i0 and the closed contact members 52a of relay 2 tothe supply conductor L-.

The energized relay to closes its contact members ilia and' lfih, thereby inserting the resistors R6, R2 and R3 in the center of the star winding MS and closing that circuit to energize the drivmg motor M. This circuit extends, one branch from supply conductor Ll through the contact members 5a, the winding it, resistor RI and the contact members lilo to the junction point l9, another branch from the conductor L2 through the contact members 5b, one coil of relay 9, the winding 28 and the-resistor R2 to the junction point is, and the other branch from supply conductor L3 through the contact members 50, one'coiiof'relay a, winding 2i, the resistor R3, the contact members iilb to the junction point the switch l0 opens the circuit by which the time limit relay -l2 was energized, thereby deenergizing that relay. After the expiration of the predetermined time for which the dashpot l2N oi the relay 12 is designed, the relay operates to open its contact members l2a and close its contact members l2b. The closing of the contact members In: completes a circuit for energizing the accelerating switch ll, which circuit extends from the supply conductor L+, through the contact members 45a of relay 45, conductor 28,

the contact members llld of relay Hi, the coil of relay ll, and the contact members l2b to the supply conductor L-.

The energization of the accelerating switch ll closes its contact members lla, llb and He. The closing of the contact members llc prepares a circuit by which either the up direction switch I or the down direction switch 2 may be energized by further operation of the car switch.

The closing of the contact members H0, and llb of the switch ll short circuits the resistors Rl, R2 and R3 in the center of the star windingsMS, thereby directly connecting the windings l8, 2', and 2| to the junction point 22 and thus causing the motor M to receive its full supply of energy from the line conductors Ll, L2 and L3. The motor M is now operating under its own power, and. is operating the generator G through rotation of the shaft to provide operating current for the hoisting motor EM as soon as-the field windings GF oi the generator are energized by operation of the car switch CS.

With this construction, it will be obvious that the motor M, which was being rotated at its normal rate of speed by the auxiliary motor, is now operating under its own power at its normal rate of speed and is ready for operating the motor generator set to effect operation of the car, and that this is effected without causing a high magnetizing peak in the motor M during its first few cycles of operation, thus preventing the flickering of the lamps and any other undesirable eflects which would otherwise be fiaused by throwing the motor directly on its It will be assumed now that the door (not shown) has closed, thus closing the door and gate contact members and that the car attendant continues operation of the car switch CS in its counter-clockwise direction, thereby closing its contact members l3 and 23 to eifect operation of the up direction switch I, by a circuit extending from supplyconductor L+ through conductor IS, the contact members l3 and 23 of the car switch, the coil of up direction switch I, the coil of auxiliary switch I, the door and gate contact members 25 and the contact members lie of switch H to the supply conductor L.

The energization of the auxiliary switch I closes its contact members la, thus completing an auxiliary circuit for the motor switch l0 and the accelerating switch ll. The auxiliary switch 1 is an interlocking switch which may be employed for various interlocking purposes as int dicated by the extra contact members lb. It is shown here for the purpose of illustrating how it may be employed to interlock the circuits for the switches l0 and ll. f

The energization of the up direction switch I closes its contact members la and lb, thereby energizing the field winding GF of the generator G for up direction operation .of the car by a circuit extending from supply of conductor L-l-., through the contact members la of switch I, the

winding GF, the contact members lb of switch I, and the resistor R4 to the supply conductor L. The energization of the field winding GF causes the generator G (now being operated by the driving motor M under its own power) to supply current to the hoisting motor EM which in turn operates the hoisting drum D to operate the car C upwardly.

It will be assumed now that the car attendant moves the car switch to full on position to operate the car at high speed. This action closes the contact members l3 and 26, thus energizing the high-speed relay by a circuit extending from supply conductor L+, through conductor l5,,

the contact members l3 and 26 of switch CS, the coil of relay 3, the coil of relay 1, the door and gate contact members 25, and the contact members llc of switch ll to the supply'conductor L-. Theenergization of the relay 3 closes its contact member 3a, thereby short circuiting the resistor R4 in the circuit of the field windings GF oi the generator G and thus causing the generator G to supply full current to the hoisting motor EM, thus causing the car C to operate upwardly at its normal high speed.

.By this operation of the system, it is seen that the auxiliary motor AM maintains the driving motor M at its normal-speed while the car is out of operation and that as soon as the car attendant operates the car-switch to start the car, the driving motor M has its star windings MS connected through the buifer resistors RI, R2 and R3 at the center of its windings MS, and that after the expiration of a predetermined time, the windings MS are directly connected at I their center point to cause the motor M to receive full power for operating the car. It will also be seen that this is accomplished by the use of simple and inexpensive two-pole switches and that the buifer resistance prevents any undesirable effects from the operation of connecting the motor M to its supply circuit.

It will be assumed now that the car attendant, desirous of stopping the car, centers the car switch CS, thereby separating the contact memto open its contact members la and lb, thus de- 2 energizing the'fleld winding GF and effecting the stopping of the hoisting motor and the car C. The separation of the contact members l3 and 23 also deenergizes the auxiliary switch 1,

thereby causing it to open its contact members la in the auixilary circuit for the switches l0 and II.

The separation of the contact members l3 and l4 of the switch CS deenergizes the motor switch l0 and the accelerating switoh- II. The deenergization of the switch ll opens its contact members H a and Ht, thereby disconnecting the central portion oi. the star windings MS from each other. bers He will prevent operation oi? the direction switches until the accelerating switch I I is again energized.

The opening or the contact members Illa and 1 motor M and also prevents any unfavorable eifect on the power factor of the supply system for the motor M while the car is idle. The opening 01' the contact members i he opens the sell-holding circuit for the relay it. The

opening of the contact members 00d will prevent energization of the relay it until switch I0 is again energized. The closing of the contact members llle reestabllshes the circuit for energizing the time limit relay l2, and that relay immediately resumes its energized position. The energized relay l2 closes its contact members l2a to prepare the circuit of the switch ill for further operation, and opens its contact members lib to prevent operation of the acceleratlng switch ll until the expiration of a predetermined time after the switch ill is energized. The system is now ready for the next cycle of operation.

By reason 01' the foregoing description, it will be seen that we have provided an elevator systern having a simple and inexpensive means for connecting the star windings of its driving motor, and that we have also provided a simple and inexpensive system for supplying resistance to the center of the star windings of that motor at the time it is connected for operation under its own power.

Although we have illustrated and described only one system embodying our invention, it is i to be understood that modifications thereof and changes therein maybe made without departing from the spirit and scope of the invention.

We claim as our invention:

1. In an elevator system for operating a car, a hoisting, motor for the car, control means for starting and stopping the hoisting motor, a generator for supplying power to said hoisting motor, a main motor for driving the generator, said main motor having a stator comprising a three-phase star winding, an auxiliary motor for rotating the main motor and, the generator when the main motor is not operating under its own power, and means responsive to operation 01 the control means in starting the hoisting motor for connecting together the center points oi said star winding to cause the mainmotor to operate under its own power when the generator is to operate the elevator moton' 2. In an elevator system for operating a car, a hoisting motor for the car, means for controlling the starting and stopping of the hoisting motor, a generator for supplying power to the hoisting motor, amain motor for driving the generator, said main motor having a stator comprising a star winding, an auxiliary motor for rotating the main motor and the generator while The opening of the contact mamthe main motor is not operating under its own power, means for connecting the outer ends of the star winding to a source of electrical energy, a two pole switch for the center of the star winding, and means responsive to operation of the control means in starting the hoisting motor for operating the two pole switch to connect together the center points of the star winding to cause the main motor to operate under its own power when the generator is to operate the hoisting motor.

3. In an elevator system for operating a car, a hoisting motor for the car, contro1 means for starting and stopping said hoisting motor, a generator for supplying power to said hoisting motor, a main motor for driving the generator, said main motor having a stator including a three-phase star winding, an auxiliary motor for rotating the main motor and the generator when .the main motor is not operating under its own power, means for connecting the auxiliary motor and the outer leads of the star winding of the main motor to a source of electrical energy, and

means responsive to operation of the control means in starting the hoisting motor for connecting together the center points of said star winding to cause that motor to operate under its own power when the generator is to operate the hoisting motor.

.4. In an elevator system for operating a car, a hoisting motor for the car, control means for starting and stopping the hoisting motor, a generator for supplying power to said hoisting motor, a main motor for-driving the generator, said main motor having a stator comprising a three-phase star winding, an auxiliary motor for rotating the main motor and the generator when the main motor is not operating under its own power, means for connecting the auxiliary motor and the outer leads of the star winding of the main motor to a source of-electrical energy, a plurality of resistors for the center of said star winding, means responsive to operation of the controlling means in starting the hoisting motor for connecting the center points of said star winding through said resistors to cause the main said main motor having a stator comprising a three-phase star winding, an auxiliary motor for rotating the main motor and the generator when the main motor is not operating under'its own power, means for connecting the auxiliary motor. and the outer'leads of the star winding of the main motor to a source oi? electrical energy, a plurality of resistors for the center of said star winding, means responsive to opera tion of the control means in starting the hoisting motor forconnecting the center points of said star winding through said resistors to cause the main motor to receive a predeterminedamount of power from its source of electrical energy and for short-circuting said resistors and directly connecting the center points of said star winding alter the expiration of a predetermined period of time to cause the main motor to receive a full supply of power from its source of electrical energy.

6. In an elevator system for operating a car, a hoisting motor for the car, control. means for starting and stopping said hoisting motor, a generator for supplying power to said hoisting motor, an exciter, a main motor for driving the generator and the exciter, said main motor having a stator comprising a three-phase star winding, an auxiliary motor for rotating the main motor, the excitei' and the generator when the main motor is not operating under its own power, means for connecting the auxiliary motor and the outer leads of the star winding'to a source of electrical energy, a time limit relay disposed to be energized by said exciter, a plurality of resistors associated with the center points of the star winding and means responsive to operation of the control means in starting the hoisting motor for deenergizing the time limit relay and for connecting the resistors in circuit with the center points of said star winding stator to cause the main motor to receive a predetermined amount of power from its source of electrical energy, and means responsive to deenergization of the time limit relay for short circuiting the said resistors and directly connecting together the center points oi said star winding to cause the main motor to then receive full power from its source of electrical energy.

'7. In an elevator system for operating a car, a hoisting motor for the car, a motor generator set comprising a main motor and a generator for supplying power to the hoisting motor, control meansfor causing the motor generator set to start and stop the hoisting motor, said main motor having a three-phase star winding stator, an auxiliary motor for rotating the main motor and the generator when the main motor isnot operating under its own power, means for connecting the auxiliary motor and the outer lead of the star winding stator of the main motor to a'source of electrical energy, a plurality of resistors associated with the center of the star winding stator, and means responsive to operation of the control means tor first connecting said resistors in the center of said star winding stator to cause the main motor to receive a predetermined amount of power from its source or electrical energy, and after the expiration of a predetermined .timevdisconnecting said resistors and directly connecting the center points of the star winding to cause the main motor to then receive full power from its source of electrical energy. 8. In an elevator system for operating a car, a hoisting motor'ior the car, control means for starting and stopping the hoisting motor, a. generator for supplying power to the hoisting motor, a main motor for driving the generator, said main. motor having a stator comprising a three-phase star winding, an auxiliary motor for rotating the main motor and the generator when the main motor is not operating under its own power, meansior connecting the auxiliary motor and the outer leads of the star winding of the main motor to a source of electrical energy, a plurality of resistors for the center of said star winding, a two-pole switch connected in the center of the star winding, a two-pole switch connected in the resistors, and means responsive to operation of the control means in starting the hoisting motor for operating the two-pole switch associated with the resistors to connect the center points of the star winding through the resistors to cause the main motor to receive a predetermined amount of power from its source of electrical energy and for subsequently operating the first named two-pole switch for short circuiting said resistors and for directly as connecting the center points of said star winding after a predetermined period of time to cause the main motor to then receive a'iull supply of power from its source of electrical energy.

EDGAR M. BOUTON. WTILIJAM A. CLARK. HAROLD W. ii -Amt 

